The prior art is replete with various types of devices for dispensing either individual doses or multiple doses of fluids or solid pellets. Representative devices are shown for example in U.S. Pat. Nos. 2,403,074, 2,768,623, and 3,154,074, which disclose various manually operated dosage forms for dispensing an individual fluid pulse; Nos. 3,736,933, 3,826,409 and 4,111,304 which disclose devices which can be used to dispense a multiplicity of fluid pulses and Nos. 3,311,229, 3,433,352, 3,737,029, and 3,780,856, all of which disclose various types of blister packages which may be used for dispensing a multiplicity of pharmaceutical dosages usually however in the solid form. U.S. Pat. No. 3,613,680 shows that it is known to include a dosage of a soluble material within a flexible bag such as a disposable syringe and No. 3,443,561 shows that it is known to implant single or multiple dosage form dispensers within the human body.
There currently exists a need for a device which is capable of dispensing multiple pulses of predetermined quantities of a fluid substance. While the applications for such devices range from chemical processing to fertilizing, and feeding fish, a major area of application is in the medical field in which the periodic administration of a precisely determined amount of a biologically active material is required. For example, with respect to insulin therapy for diabetes, one of the most common therapeutic techniques comprises the injection of a predetermined amount of insulin at various times during the day. Thus, for example, according to this invention rather than the conventional multiple hypodermic injections, one insertion could be employed which would thereafter serve to introduce a series of pulse dosages rather than have separate repeated punctures thereafter. Similarly, in a more advanced form of insulin therapy employing a small pump such as is disclosed and claimed U.S. Pat. No. 4,340,048 of Eckenhoff for Self Driven Hypodermic Injector; a continuous basal infusion rate can be provided which is supplemented with manually instigated pulses to more precisely adjust to the changing needs of the patient such as occur after eating, for example. Similarly, in various other forms of therapy, periodic pulse dosages of antibiotics or nutrients are added to IV lines, but normally require a separate insertion of a needle or the introduction of a new mini-bag.
In the administration of pulse doses, it is desirable that manual operation be employed and that there be a positive and irreversible dispensing action such that partial dosages cannot be administered nor can dispensed material be sucked back into the device. In addition, it would be desirable that means for dispensing various dosages in various sequences be available and that the condition of the device in terms of amount dispensed and amount still available can be readily and simply observed visually. While devices of the prior art may be capable of performing one or more of these functions, no device is known which has all of the desirable attributes aforementioned, in addition to being simple and inexpensive to construct and extremely compact in size.
Accordingly, it is an object of this invention to provide a manually operated multipulse fluid dispenser.
It is another object of this invention to provide a multidose dispenser in which the status of use is visually observable.
It is another object of this invention to provide a multidose dispenser in which the size of the dose dispensed can be varied in any sequence.
It is another object of this invention to provide a multidose dispenser in which the manually operated dispensing action is irreversible.